1. Field
The present invention relates to an electrosurgical device and, in particular, to a cutting device for use with a catheter device inserted into a body.
2. Background Art
Medicine is providing ever-increasing demands for devices that can navigate narrow passageways to a desired location within a body so that diagnostic and therapeutic procedures can be performed at that location. Currently, elongated medical devices such as catheters can extend into a body from outside via an access point through various connected passageways to a desired location. At this location, it is desirable that an electrosurgical procedure be one of the procedures that are made available.
An electrosurgical procedure involves a medical device that uses electrical energy to perform a procedure, such as coagulation, dissection, desiccation and cautery. The electrical energy can be provided in either direct current (DC) form or in alternating current (AC) form. However, low frequency electrical energy, including DC, can stimulate muscle and nerves and have potentially undesirable outcomes such as cardiac arrest, if not properly handled. Higher frequency electrical energy, and in particular electrical energy in the radiofrequency (RF) range, does not stimulate muscle or nerves, and can therefore be used to core and coagulate tissue.
Modern day elongated medical devices provide the ability for clinicians to navigate to remote and narrow locations within a body. To provide such access, these elongated medical devices must meet a wide variety of requirements such as a desired length and a sufficiently small outer diameter. Further, such a device must also have a sufficiently large inside diameter to permit navigation and delivery of the required functionality to the remote location. In the case of an RF-powered electrosurgical device located at the end of such an elongated medical device, the inside diameter needs to be both sufficiently large to transfer the required energy of the electrosurgical device, as well as provide sufficient diameter consistent with the aspiration requirements of the device. More specifically, sufficient electrical current needs to be delivered to support the RF power level desired at the particular location in the body. In the case of a coring procedure, the size of the inner diameter of the cutting device must also permit the required aspiration of cored tissue from that location. Further, it is necessary to ensure that the heat generated in the immediate vicinity of the cutting device be sufficiently isolated from the rest of the elongated medical device so that the elongated medical device does not deteriorate or self-destruct under the resulting thermal conditions.